Spherical Bi2MoO6 with oxygen vacancies via solvent manipulation for enhanced photocatalytic NO removal

High specific surface area and moderate oxygen vacancies concentration are two effective solutions for enhancing photocatalytic removal of NO. In this work, we synthesized self-assembled spherical Bi2MoO6 with oxygen vacancies by altering the solvent used in the hydrothermal process. Under visible light (lambda>420 nm) irradiation, the photocatalytic removal rate of NO by ethanol-glycol mediated Bi2MoO6 nanospheres reached 57 %. Based on a series of characterization, it is found that the generation of appropriate oxygen vacancy and the increase of specific surface area are considered to be the reasons for the improvement of photocatalytic activity. When the solvent was changed, the specific surface area of Bi2MoO6 increased from the lowest 7.18 m(2)/g to 60.96 m(2)/g, and the increase of specific surface area could provide more active sites for photocatalytic reaction. Secondly, the appearance of oxygen vacancy improves the photocatalytic performance of Bi2MoO6, but with the continuous increase of oxygen vacancy concentration (the concentration is about 3 times before), the catalytic performance is greatly reduced. This shows that a moderate amount of oxygen vacancy can improve the photocatalytic activity, but excessive oxygen vacancy will hinder the photocatalytic reaction. Furthermore, in situ DRIFTS are used to further reveal the pathways and mechanism of photocatalytic NO removal. This work offers an effective strategy for preparing spherical layered bismuth-based materials with oxygen vacancies for air purification.